Research On Methods Of Transiant Power Quality Recognition Based On Wavelet Transform

With the rapid economic development, sensitive loads such as personal computers andkinds of electronic devices increased rapidly in power system. Any power quality problemmay lead to huge economy losses. Power quality problem has been an important problemwhich cannot be ignored by every walk of life. This paper mainly made research on theapplication of wavelet transform in transient power quality disturbances recognition, and madeworks as follows:This paper analyzed the causes, typical features and evaluation standards of all kinds ofpower quality problems, and made meticulous description on five types of common transientpower quality disturbances.This paper made further research on the principle of wavelet transform. The disturbancesof power quality can be located according to the characteristics of transient power qualitydisturbances and in using of wavelet singularity detection principle. On this basis, this paperanalyzed the deficiency of this algorithm in detail.This paper made further study on the principle of wavelet de-noising, and chose animproved threshold function which is between the soft and hard threshold function to de-noisethe disturbed signal. The experiment result showed that the noise can be eliminated and thesingularity of signal can be kept by this threshold function. The de-noising effect of thisfunction is better than traditional soft and hard threshold function.Finally, this paper improved a method for transient disturbance identification which isbased on db1wavelets’ d6modulus maxima, and designed the detailed process of transientdisturbance recognition. In using of double wavelets, we realized precise classification andpositioning of all kinds of transient disturbances.